Some useful tricks I found, hopefully this helps someone out!
(Sorry, If I post in the wrong area, I'm new to the forums)
Frog - You can use them to jump across the colored water(Goo)(Throwing them, then jumping off their heads)
Dart Gun - You can almost fully scale a whole wall using this!
Forceball - Using this in a corner and jumping, You can get a HUGE boost up to a Gem, Yarn, Ledge
You can add me if you guys want to play GT: Hateside